Coitus results in the introduction of sperm, seminal lymphoid cells and soluble semen components into the female lower genital tract. The factors influencing the female immune response to these semen components remain to be determined. Delineation of the qualitative and quantitative aspects of this response are especially needed at this time, in the presence of the AIDS pandemic. Human immunodeficiency virus (HIV), the cause of AIDS, is principally transmitted worldwide via coitus and females, especially, are most likely to become infected via coitus with an HIV-infected man. Development of methods and recommendations to minimize this heterosexual transmission of HIV requires a thorough understanding of the variables influencing how a female would respond to coitus. We propose to examine the pattern of cytokines (IL1, IL2,IL4, IL6, IL10, TNF-alpha, IFN-gamma) and cytokine regulatory proteins (IL1 receptor antagonist, soluble IL6 receptor, soluble TNF receptor, TGF-beta) present in the vagina- exocervix, endocervix and circulation, and the concentration of lymphoid cells in the circulation and in the endocervix, prior to and following coitus in women using no contraception, in women using diaphragm plus spermicide, oral contraceptives, condoms or intrauterine devices and in female partners of vasectomized men who subsequently will undergo a vasectomy reversal. The effect of either partner being sensitized to sperm, the presence of a genital tract allergic response or an asymptomatic genital tract infection with Chlamydia trachomatis, Neisseria gonorrheae, Trichomonas vaginalis, Candida albicans, Bacteroids fragilis, Ureaplasma urealyticum, Mycoplasma hominis, Cytomegalovirus, Herpesvirus, or bacterial vaginosis on the females' cytokine and lymphoid cell responses to coitus will also be determined. The induction of cytokines indicative of activation of subclasses of T lymphocytes-T/H/0, T/H/1, and T/H/2 cells- will be emphasized since the susceptibility to contracting HIV is believed to be enhanced in the presence of a T/H/2 response and diminished in the presence of a T/H/1 response.